Keycap Row Codes and Profile Heights: What Is Documented

Keycap row codes identify positions within a manufacturer’s profile family. They do not give a universal height in millimetres. An R1 replacement can belong at the top of one set and the bottom of another. Match the manufacturer, profile family and physical keyboard row before using a height figure to compare parts.

This reference preserves the vendor row-code comparison documented by Deskthority and separates it from dimensional evidence. It is intended for reading kit diagrams and replacement-key listings. For widths and bottom-row coverage, use keycap sizes explained.

Keycap row codes by vendor

The following table follows Deskthority’s keyboard-profile reference. Treat it as a translation aid for the families recorded there; a current set’s own kit diagram remains the reference for that set. A vendor name alone is insufficient when the vendor offers several profile families.

Physical keyboard row	Signature Plastics	QWERKeys	WASD	Cherry	Leopold	Topre	KAT	MDA
Function row	1 (DCS uses 5)	1	4	E	E	E	5	1 or 0
Number row	1	1	4	E	E	E	4	1
Tab row (QWER)	2	2	3	D	D	D	3	2
Home row (ASDF)	3	3	2	C	C	C	2	3
Bottom alphabetic row (ZXCV)	4	4	1	B	B	B	1	4
Space bar row	3 or 4	4	1	B	B	B	1	4 (convex 5)

The number row shows the problem clearly: Signature Plastics uses 1, WASD uses 4 and Cherry uses E in this reference. The same physical position has three labels. Conversely, the label 1 can describe different physical positions.

Do not silently combine the bottom alphabetic row and the space bar row. The table records alternatives for Signature Plastics and a convex option for MDA. Function-row exceptions also matter: the DCS and KAT entries differ from their number-row entries. A four-row kit diagram cannot by itself describe all six rows of a full keyboard.

How to decode a replacement key

Start with the physical position rather than the legend. Write down whether the missing cap belongs on the number, Tab, home, bottom alphabetic or space bar row. Then identify the profile family printed on the kit page. Only after those two checks should a row number enter the comparison.

For example, a home-row replacement corresponds to SP 3, Cherry C, WASD 2, KAT 2 or MDA 3 in the table. These labels locate a row; they do not establish that caps from all five families have the same slope, wall shape or height. Matching the row code is one part of a replacement specification.

Also record width in units and whether the key is stepped, convex or fitted with stabiliser sockets. A correctly labelled row cannot compensate for the wrong key width. Use the row-code decoder in the keycap sizer as a quick lookup, then confirm the actual part against its kit diagram.

What a profile height in millimetres describes

Deskthority distinguishes sculptured profiles, which vary by row, from uniform profiles. Signature Plastics likewise describes DCS as sculptured and cylindrical, and DSA as non-sculptured and spherical. A single height for an entire sculptured set leaves out the row being described.

Before comparing two numbers, establish their measurement basis. Does the source describe a loose cap from its base to its tallest edge, the centre of the dished top, or the cap installed on a switch? Is it the tallest row in the set or the home row? These questions identify different dimensions. Subtracting unlike figures does not yield a useful clearance estimate.

The sources cited here do not supply a complete, manufacturer-controlled Cherry-versus-OEM row-height table. That is a limit of this reference, rather than evidence that no manufacturer could publish one. Values from community charts need their original set, row and measuring point before they can serve as replacement-part dimensions.

The documented DSA height anchor

Deskthority records the Signature Plastics DSA family at 0.291 inches high, approximately 7.39 mm, and relates it to OEM home-row height. The conversion is 0.291 multiplied by 25.4, or 7.3914 mm before rounding. This is a value reported by a community reference, not a measurement made by this desk.

The useful result is a named family and an attributable height. The limitation is equally specific: the reference does not establish a tolerance band for every DSA production run or make 7.39 mm a guaranteed height for every OEM manufacturer’s home-row cap.

Reference entry	What it supports	What it does not establish
DSA: 0.291 inches, about 7.39 mm	The family height reported by Deskthority	A measured value for an individual delivered cap
DSA compared with OEM home row	The comparison made in that reference	A universal OEM tooling specification
Vendor row-code table	Translation between documented row labels	Interchangeability or equal millimetre heights

Keep the rounding visible. Writing 7.3914 mm merely because a calculator produces four decimal places would imply more precision than the source supports.

DCS row sculpting and mixed sets

Deskthority describes DCS as similar to Cherry profile while recording a difference in bottom-row slant. That makes the bottom rows a specific place to check when combining DCS parts with another sculptured set. Similar family descriptions do not guarantee a continuous top surface after mixing parts.

The DCS reference also documents internal construction details, including the absence of supporting struts around the keycap stem. Those details belong to that profile’s construction and should not be inferred from its row code. For plastic construction and published thickness examples, see keycap wall thickness by material.

Uniform profiles reduce the row-shape issue. Signature Plastics describes DSA as non-sculptured, so its family description does not assign a different sculptured angle to each alphabetic row. Width, mount and special-key shape still need their own checks. A uniform set is not automatically a complete kit for an arbitrary layout.

A useful record for a dimensional query

When a listing leaves a replacement ambiguous, collect the set name, profile family, row label, physical row, key width and a link to the kit diagram. If a published height is involved, include the stated measuring point and whether the cap is installed. Preserve the source’s units and any tolerance rather than rounding first and asking questions later.

If two caps share a row label but sit differently, compare the diagrams before treating either as defective. If a correctly matched cap moves on the switch, continue with keycap wobble diagnosis. Row identity explains placement; the cap socket, switch and stabilisers require a separate fit check.